JPH0481067A - Image sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an image sensor, and particularly to an image sensor used for reading a document in a scanning copying machine, an electronic filing device, a manual drawing device, etc. Regarding sensors.

(Prior Art) Regarding image sensors used in the document reading section of facsimile machines and scanning copying machines, in recent years, the use of contact-type image sensors has increased in order to downsize devices and simplify maintenance. There is.

This contact image sensor uses a focusing rod lens array in the lens system to form an erect, 1:1 image of the original onto a photoelectric conversion element array with a length equal to the width of the original to obtain an image signal. It is something. This contact type image sensor has a short focusing distance of the Rondo lens array, so
It has the feature of being able to miniaturize the device.

In addition, contact image sensors have a larger light-receiving area and better sensitivity than conventional reduction-type image sensors, which use a lens to reduce the image and form it on the sensor surface.As a light source for illumination, they have a long life with fewer failures. Solid state light emitting devices such as LEDs can be used. Therefore, it has the advantage that maintenance of the light source is almost unnecessary.

Generally, a contact image sensor requires a reading width of the same size as the document width, that is, a photoelectric conversion element array length. Alternatively, a device in which a predetermined length is obtained by arranging a plurality of IC image sensor chips such as CCDs is used.

FIG. 3 is a partially sectional perspective view showing the structure of a conventional contact type image sensor. A plurality of CCD image sensor chips 31 are arranged linearly on an alumina substrate 32. Furthermore, the alumina substrate 32 is attached with adhesive 34 so as to cover the image sensor chip 31 using the cover crow 33.
is glued to. This cover glass 33 is made by bending a thin glass plate to form a trapezoidal shape as a whole, and the image sensor chimney is located in the central recess to protect the CCD image sensor 31. There is.

The reason for this structure is that the alumina substrate 32 needs to be longer than the document width (for example, A4 size is 216 mm), so it is difficult to form a recess by laminating the alumina substrates themselves. Therefore, as in this example, the substrate is usually flat, and the cover glass 33 is melt-molded to form a recess to provide a space in which to house the CCD image sensor chip 31.

(Problem to be solved by the invention) When melting and molding such a cover glass, a flat plate glass is placed in a mold made of carbon, etc., and molded by passing it through a furnace to raise the temperature to above the softening point of the glass (usually around 800°C). do. At this time, it is difficult to uniformly raise the temperature of a long piece due to temperature distribution problems in the furnace, so generally the length of the piece is about 350 m+i, that is, A3 size.

Recently, it is necessary to read larger originals, such as approximately 600 mm for Al size and approximately 850 mm+ for AO size, in scanning copying machines, manual drawing machines, and the like. but,
It is difficult to produce a large cover glass that can meet these demands using conventional melt molding. For this reason, it is not possible to form a large cover glass by joining together small cover glasses because it causes disturbance of the optical path at the joint. Further, even if a large cover glass can be manufactured using current technology, there is a problem that the surface flatness is not good and the light incident characteristics vary, which deteriorates the characteristics as an image sensor.

The present invention was made to solve these problems, and an object of the present invention is to provide a large-sized image sensor that is easy to manufacture and has high optical characteristics.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides an image sensor having a transparent cover installed on a substrate so as to surround a light receiving surface of an image sensor chip placed on the substrate. It is formed by pasting together a frame material arranged parallel to both sides of the sensor chip and having a thickness at least thicker than the image sensor chip, and a transparent flat plate spanned between the upper surfaces of this frame material. It is characterized by this.

It is preferable that the transparent flat plate is made of flat glass.

It is preferable that the frame material is made of the same material as the flat glass.

It is preferable that low melting point glass is used for bonding the frame material and the flat glass.

(Function) In the present invention, since the transparent cover is formed by laminating the transparent flat plate and the frame material, it can be formed stably at a temperature sufficiently lower than the softening point of glass, and is hardly affected by temperature variations. be able to.

Furthermore, if the flat glass and the frame material are made of the same material, distortion will not occur and a large transparent cover can be easily formed.

(Embodiment) FIG. 1 is a partially sectional perspective view showing an image sensor according to an embodiment of the present invention. A plurality of CCD image sensor chips 11 are successively mounted on an alumina substrate 12 in a straight line.

Further, a transparent cover 13 is bonded to the alumina substrate 12 with an adhesive 14 to protect the CCD image sensor chip 11.

In the case of the present invention, the transparent cover 13 includes two frame members 13a and 13b arranged in parallel on both sides of the CCD image sensor chip 11, and a deck glass 13c spanned between the upper surfaces of the frame members 13a213b. It is formed by pasting together. In this case, the thickness of the frame members 13a and 13b is equal to or thicker than the thickness of the image sensor chip 11.

FIG. 2 is a perspective view showing an example of the assembly of the transparent cover 13 used in the present invention. This transparent cover is flat glass 2
1 and a frame material 22, 2 made of the same material as this flat glass 21.
3,24. ．． 25 are bonded together with a low melting point glass 26, and the frame members 22, 23, 24, and 25 are bonded together with a low melting point glass 26. The bonding using the low melting point glass 26 is carried out at a temperature of about 420° C., which is sufficiently lower than the softening point of the glass, and moreover, at a temperature higher than the melting point of the low melting point glass 26. Under such temperature conditions, stable fusion can be performed without being affected by temperature variations.

Here, the flat glass 21 and the frame material 22. 23. 2425
If they are made of the same material, the thermal expansion coefficients will be the same, so no distortion will occur, and it will be possible to easily form a large cover exceeding 600 mm.

Such a cover is prepared in advance, and the image sensor is completed by adhering this cover after fixing the CCD image sensor chip onto the alumina substrate.

Note that as the image sensor chip 11, a bipolar type or MOS type image sensor chip can be used in addition to a CCD.

Furthermore, the frame material does not necessarily have to be glass; for example, if resin is used, an epoxy adhesive or the like can be used to bond the transparent flat plate and the frame material. In this case, it is preferable that the transparent flat plate and the frame material have the same coefficient of thermal expansion to prevent warping.

Furthermore, since the frame material does not directly contribute to the incidence of light, it does not need to be transparent.

〔Effect of the invention〕

As explained above, in the present invention, a cover having a concave portion corresponding to an image sensor chip is formed by bonding flat glass and a frame material, so a large cover that could not be realized by conventional melt molding can be formed. It can be made without distortion. Therefore, even in the case of a large image sensor, for example, over 600 mm, by protecting the image sensor chip using the second large cover, it is possible to obtain high quality read images and high reliability.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional perspective view of an image sensor according to an embodiment of the present invention, FIG. 2 is a perspective view showing how a transparent cover used in the present invention is assembled, and FIG. 3 is a perspective view of a conventional image sensor. It is a partially sectional perspective view shown. 11... CCD image sensor chip, 12... Alumina substrate, 13... Transparent cover, 1.3 a...
Frame material, 13b...Flat glass, 14...Adhesive, 21
... Flat glass, 22.23, 24.25 ... Frame material,
26...Low melting point glass. Applicant's agent Sato - Yushu 3

Claims (1)

[Claims] 1. An image sensor having a transparent cover installed on the substrate so as to surround the light-receiving surface of an image sensor chip placed on the substrate, wherein the transparent cover covers both sides of the image sensor chip. It is characterized by being formed by pasting together a frame material arranged parallel to the image sensor chip and having a thickness at least thicker than the image sensor chip, and a transparent flat plate spanned between the upper surfaces of the frame material. image sensor. 2. The image sensor according to claim 1, wherein the transparent flat plate is made of flat glass. 3. The image sensor according to claim 2, wherein the frame material is made of the same material as the flat glass. 4. The image sensor according to claim 3, wherein low melting point glass is used for bonding the frame material and the flat glass.